Such apparatus are those used for iontophoresis, electro-osmosis and similar treatments, based on the migration of electric charges in order to allow penetration of substances to be administered through the skin.
The abovementioned apparatus are basically formed by a power supply unit which supplies the required voltage and electric current to electrodes connected thereto; the substances to be administered are dispersed in ionic or molecular form, in a carrier fluid contained in an applicator unit which is brought into contact with the skin of the area of the body to be treated, so as to allow the passage of the substances via electrophoretic migration.
Depending on the configuration of the applicator unit, the apparatus considered herein can be divided into two separate groups.
The first group comprises those apparatus in which said unit is essentially formed by a head, also called “dispenser”, operated manually in order to perform passes along the area of the body to be treated; according to one embodiment, the applicator head is provided with a roller, above which a container with the carrier fluid is arranged upside-down.
Said fluid moves down from the container and licks an electrode in such a way that the ion substances to be administered and dispersed therein, can pass through the skin, as a result of the rolling of the roller which spreads the carrier fluid over the patient's skin with each pass of the applicator head; an example of this state of the art is described in Italian patent application No. FI99A00055 of Mar. 22, 1999.
The apparatus of the second group referred to above, are those wherein the applicator unit is essentially a compress, also called a “patch”, which is placed on the area of the body to be treated.
Examples of these apparatus are described in several documents and publications, including European patent application No. 292,930 and U.S. Pat. No. 5,084,008.
In these cases the patch has the function of a container for the carrier fluid and has a wall permeable to the substances to be administered, which can be formed by means of an osmotic membrane, a flexible mesh, or the like; an electrode associated with the container causes the migration, on an ionic level, of said substances, which for this purpose pass through the permeable wall placed on the skin of the area of the body to be treated.
The electrode of these known apparatus is usually a mesh or a metallic plate present in the patch, but can also be a wall of the latter, indeed, the container which forms the patches is generally rigid, so that by forming or lining one or more of its walls with metallic material, they can act as electrodes.
However, both groups of apparatus referred to above have intrinsic limitations in their operation, which make them unsuitable for certain applications.
Indeed, the apparatus with dispenser operated manually allow substances to be delivered deeply because the flow of the electric charges is concentrated in few points, which in the case considered above are those around the contact generatrix of the rolling roller on the skin.
However, since the dispenser must be operated manually, these apparatus require the continuous presence of an operator: therefore they are not very advantageous in terms of costs since the staff of hospitals, clinics and the like must attend to the treatment sessions for all duration thereof.
It should also be borne in mind that, for the same reasons, it is not possible to treat several parts of the body at the same time, nor several patients at the same time (one operator could not be able handle two dispensers at the same time); if, in addition to this, it is considered that human intervention is inevitably a source of lack of uniformity in the treatments performed by different operators (an other factors being equal), it can be understood how this type of apparatus has limitations either from the point of view of service management (in hospitals, outpatients' departments etc.), and from the point of view of the regularity of the treatments performed.
On the contrary, in the case of apparatus with an applicator patch these limitations are overcome: indeed, once the patch has been positioned on the are of the body to be treated and connected to the power supply unit programmed for the treatment, there is an fact no more need for any action by an operator.
However, this type of apparatus has some problems from the point of view of substances delivery.
Indeed, these apparatus do not allow deeply located tissues to be reached effectively; this is due to the fact that in order to obtain certain levels of penetration, excessively high voltage and/or current values would have to be applied to the electrodes.